Full-Stack AI Engineer

• Bachelor's or Master's degree in Computer Science, Software Engineering, or a related field.

• Solid TypeScript and Python skills, with experience shipping production web applications in React. We mean real software used by real people, beyond scripts or notebooks.

• Hands-on experience with LLMs: prompt engineering, function calling, RAG, or fine-tuning.

• Business sense. You understand how a company operates (stock, purchasing, orders, costs) and you design software around the real process behind it.

• A critical, proactive mindset. You question requirements and propose better alternatives instead of agreeing to everything. You plan your own work and deliver on the deadlines you commit to.

• Willingness to reside in or relocate to Barcelona.

• Experience building agents or multi-step LLM pipelines with LangChain, LlamaIndex, or custom frameworks.

• Experience with vector databases, embedding-based retrieval or evaluation frameworks for LLM output quality.

• Experience building internal tools, ERPs or business software for inventory, purchasing or operations.

• Background in developer tooling, internal platforms, or MLOps.

• Being part of a fast-growing robotics and AI company with genuine ambition, where your career can accelerate alongside us.

• The chance to own THEKER's internal AI tooling from the ground up, with direct visibility into the impact your work has on the entire engineering team.

• A focused, talent-dense team where your work is visible and your decisions count.

• An environment where new ideas are encouraged and your contributions shape both the product and the company.

• 100% on-site work in Barcelona.

We are looking for a Full-stack AI Engineer to build the internal software and AI tools that THEKER runs on. This is a hands-on engineering role focused on shipping. You'll build full applications end to end, from the data model to the interface people use every day, and you'll bring LLMs into them wherever they remove real friction.

You'll work with engineering and operations teams, and with the people who keep the business running. That means internal platforms like stock or purchasing modules, LLM integrations, internal agents, retrieval systems and whatever else removes bottlenecks. Before writing code, you'll understand the process behind it. If you're building a stock module, you know what stock means for a company that builds and deploys robots.

We don't want someone who says yes to everything. You'll question requirements, push back when something doesn't add up and come back with a better proposal. You'll own your deadlines and move projects forward without waiting to be asked. A good quarter in this role means our teams spend less time on repetitive work and more time on the problems only they can solve.

• Build and maintain internal applications end to end in TypeScript and React, from the data model to the interface.

• Design LLM-powered pipelines for code generation assistance, documentation, data extraction and process automation.

• Develop retrieval-augmented generation systems over THEKER's internal knowledge base.

• Build evaluation frameworks to measure and improve the reliability of AI tool outputs.

• Translate business processes into software. Understand how stock, purchasing or operations work before designing the tool that supports them.

• Challenge requirements and propose better approaches when the brief doesn't solve the real problem.

• Own your project timelines. Flag risks early and deliver what you commit to.

• Identify high-leverage opportunities to apply software and AI across the company and scope them into concrete projects.

• You're excited by a fast-paced and ambitious environment. The opportunity ahead of us is enormous, and we're going all in to capture it.

• You want responsibility early on, delivering at world-class standards for leading clients.

• You enjoy experimenting, iterating quickly, and embracing change as part of the learning process.

• You get energy from watching your tools get used every day, and from the feedback loop of building for a team you sit next to.